Code Breaker: crack your friend’s secret code

The classic logic game, played over a link

Code Breaker is one of the oldest pencil-and-paper games there is. With numbers it’s called Bulls and Cows; with coloured pegs, millions know it as the board game Mastermind. The idea fits in a sentence: guess a secret code, and after every guess you only learn how many of your digits are right, never which ones. From those two little numbers you work out the code like a detective.

On BeatMe you play it against someone you know. Each of you locks in a code for the other, then you take turns guessing. Make a game, send the link in any chat, and play live or one guess at a time. The codes stay on our server, so nobody can peek, and every hint is worked out there too.

The rules in short

• Duel (the classic): you each pick a secret code and take turns guessing the other’s. Both of you always get the same number of guesses.
• Race: our server picks one code, and you both crack it at the same time. Fewer guesses win, and on a tie the faster player.
• Green means a right digit in the right place. Yellow means a right digit in the wrong place. You learn how many, never which ones.
• Code length: 3 for a quick game, 4 for the classic, 5 for a real puzzle.
• Digits or colours: digits 0 to 9, or six colours, each with its own shape, so they work for children and for colour blindness too.
• Repeats: by the classic rules every digit appears only once (as in Bulls and Cows), while colours may repeat; switch repeats on for a harder code like 7 7 0 1.

How to crack a code fast

Start with guesses that test many digits at once: 1 2 3 4, then 5 6 7 8. Between them, those two guesses tell you how many of the code’s digits are 9 or 0. Then move one digit at a time: if a green turns into a yellow, you know exactly which digit was in the right place.

Every guess should be one that could still be the answer. Check it against all your earlier hints before you tap Check. A good player cracks four different digits in five to seven guesses, and with practice you’ll get there too.

A fair game with hidden codes

Your code goes to our server and never reaches your friend’s phone until the game is over. The hints are worked out there too, so nobody can fake a peg. In a race, you see only your friend’s pegs, never their guesses, until you’re done yourself.